To spray or not to spray… The decision is…. ECONOMIC!
Pesticide Economics Economic threshold—level where economic losses caused by pest damage equal cost of applying a pesticide Spraying beyond threshold… -can increase pest resistance and costs Ever-increasing levels? Pesticide Treadmill Increased pesticide use (above “needed” levels) can also result from: Spraying extra to make fruits/veggies pretty (cosmetic spraying)
INTEGRATED PEST MANAGEMENT I ntegrated P est M anagement (IPM) is an approach to managing pests such as insects, diseases, weeds and animals by integrating appropriate: Physical/Cultivation Biological Chemical …tactics that are safe, profitable and environmentally compatible.
First Level of Pesticide Alternatives: Cultivation practices Crop rotation Tree breaks/plant breaks Polyculture—intercropping, agroforestry, polyvarietal planting Planting “trap crops” Genetic/Cultivated solutions—plants “resistant” to pests/diseases BUT the pests evolve!!
Biologically-based Pesticide Alternatives Biological Solutions Natural enemies—ladybugs, parasitic wasps What are pros and cons of this? Good: focuses on target, self-perpetuating, minimize genetic resistance in pests Bad: takes years of research, may be hard to mass produce, can be done incorrectly! What about introducing NON-NATIVE species??
Sex and Hormones Releasing sterilized males into the wild Both work, but costly and time-consuming on research end Developmental stops—releasing hormones into the wild to prevent an insect from developing
Chemical Methods – Two tiers First: Naturally-occuring: Insecticidal soaps, rotenoids, Bt, cayenne pepper Bt – bacillus thuringensis toxin from soil bacteria that is naturally toxic to many insect species. Also in GM corn Only then, as a last resort: Conventional pesticides – Atrazine, organophosphates, carbamates (organo- chlorine compounds like DDT bioaccumulate, biomagnify and are used much less now)